The Harris County Toll Road Authority noted a significant increase in toll violations and images over several years. To understand the root causes behind the increase, the agency initiated a detailed toll transaction audit explicitly focused on the roadside systems. The audit objectives included tasks such as analyzing the accuracy of the roadside systems in the collection of toll transaction data, evaluating the impact of software, hardware, and configuration changes over time, and identifying potential force majeure event impacts on traffic patterns and historical trends.

AUDIT TASKS PERFORMED

  • RSS Comms/Data Transaction

  • Transaction Processing

  • Image Review

  • Interoperability
    Violation Processing

  • Toll Rate Validation

  • Vehicle Classification

  • Tag Read Validation

  • Image Capture Analysis

  • Optical Character Recognition (OCR)

  • Hardware Configuration

  • Interface Control Document

  • Transaction Files

  • Time Synchronization

The Milligan team approached the audit with a four-step process. The first was to assess the existing data to ensure it was accurate and reflected the violation increase as initially noted. The second was to evaluate the roadside systems by collecting data associated with vehicle detection, image capture, vehicle classification, transaction framing, failure and maintenance events, and then analyzing it holistically to find potential anomalies. The third step was to investigate system upgrades, software deployments, lane additions, and force majeure events to compare against notable violation spikes and evaluate their correlation. Finally, step four included working with various stakeholders from the agency and the roadside vendor to support the data evaluation, ensure accurate timelines, and validate configurations, deployments, upgrades, etc., to build confidence in the overall analysis.

The team developed a final report that included data visualizations and a presentation for the agency and concluded the project by providing several recommendations for improving the analysis and understanding of transaction trends over time.